Washer Flooding | Won’t Stop Filling

When a washing machine will not stop filling with water, and the water runs over the top, or out the front door and floods the laundry room, it’s probably an indication that there is a problem with the pressure switch, the water valve, or the hose that connects the pressure switch to the wash tub.

Because house water supply pressure varies wildly depending on venue, and whether or not you are on a pump, or a city water supply, washing machine manufacturers had to find a way to ensure that there would be sufficient water in the washer to wash the clothes.

They could not use a timing mechanism because in low water pressure situitions, it might not be enough water, and in areas with high water pressure, it may be too much water.

The solution was to use a closed pressure system that depends on the amount of water that is actually in the tub, regardless of the water supply pressure. All washing machines used in homes today, still rely on a water level control system designed years ago. So how does that work? And how does that relate to an overfilling washer?

Every washing machine has a water level control switch that uses air pressure forced through a small hose attached to an air bell on the washer tub, to control the amount of water that enters the machine. The water level control switch is usually located in the control panel of the washing machine, but can also be mounted somewhere else on the machine, usually near the top. As water enters the machine, air is forced into the air bell with the small hose attached at the top. The hose on the top of the air bell extends all the way to the water level control switch. When the air pressure in the hose is sufficient, based on the amount of water that is in the washer, a set of contacts in the water level control switch opens and disconnects the electrical path to the washer fill valve. And of course water stops entering the machine. Another set of contacts within the switch now complete a circuit to the washer motor, and the washing machine starts to agitate.

If the water level control switch is defective, or more commonly, if the small hose attached to the air bell comes off, there will no longer be pressure in the hose pushing on the air tight diaphragm in the water level control switch. The switch will not be able to open the electrical contacts to the washer fill valve and the washer will not stop filling. Water will run over the top, onto the floor, and on and on. The very first thing you should look for if you have a washing machine that is flooding, or overfilling, is whether or not the small tubing has come off the top of the air bell. Sometimes when a washing machine vibrates with an unbalanced load, there is sufficient movement to pull the tube off the top of the air bell. If you find that you have this condition, make sure that you use a good adhesive, to secure the tubing to the air bell. Just be careful that you do not get any adhesive in the tube. If you find that you have a defective water level control switch, it’s probably wise to replace the tubing also. If the tubing has not come off the air bell, and the water level control switch is not defective, the possibility exists that you have a defective washer fill valve. A washer fill valve uses an electromagnetic coil, to lift up a plunger that opens a gate to allow water to enter the machine. If debris in the fill valve prevents the gate from closing all the way, the water will continue to flow in the washer even if it is disconnected from the electrical supply. In summary, if you have a washing machine that is flooding or overfilling, check the water level control switch, the tubing attached to it, or the water fill valve.